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Download Nervous System - Emery
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Vertebrate Nervous Systems Two major subsystems: 1. central nervous system (CNS) 2. peripheral nervous system (PNS) Central Nervous System Two main components: 1. brain 2. spinal cord Brain Spinal Cord Miami Project – Spinal Cord Injury Research Peripheral Nervous System Contains two main nerve types: 1. somatic nerves involved with voluntary movement senses / movement 2. autonomic nerves involved with involuntary movement sympathetic / parasympathetic systems Cells of the Nervous System Two major cell types: 1. neurons conduct electrical signals 2. glial cells structural & insulating support for neurons Neuron Structure dendrites axon terminal soma node of Ranvier axon nucleus glial cell Glial Cells Neuron Signalling How do electrical signals pass through cells? Membrane Potential glial cells provide insulation for electrical impulses to pass through axon glial cell membrane has a lot of lipid molecules called a myelin sheath neurilemma - myelin sheaths wrapped around each other Glial Cell Grey / White Matter Why are brains said to be made of grey and white matter? white matter – neurons with neurilemma grey matter – neruons without neurilemma Grey / White Matter Neuron Types Sensory Neuron also known as afferent neurons carries signals from sensory receptors to the CNS for processing photoreceptors (eyes) chemoreceptors (nose) thermoreceptors (skin) found in clusters of neurons—ganglia Ganglia Neuron Types Interneuron also known as association neurons receives incoming signals from sensory neurons delivers outgoing signals to neurons responsible for responses Neuron Types Motor Neuron also known as efferent neurons connected to tissues that respond according what was detected muscle contraction gland secretion Neuron Responses Does all information detected by your senses go through your brain? reflex arc – connects sensory and motor neurons without going to the brain Neuron Repair Do neurons regenerate? Yes. Peripheral system neurons will repair faster than central system neurons.
